1. Field of the Invention
The present invention relates to tourniquets as used on a limb of a patient. More particularly, the present invention the relates to those tourniquets that are used for the drawing of blood from the patient's limb. More particularly, the present invention relates to auto-release mechanisms for mechanically releasing the tension of the tourniquet upon the limb of the patient.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
Tourniquets are commonly used throughout the medical profession. Tourniquets are typically used so as to occlude the movement of blood. Typically, during the drawing of blood from a limb of a patient, a tourniquet is applied around a portion of the limb. This facilitates the ability to utilize a syringe, needle or catheter for the removal of blood. After the blood is drawn, the tourniquet is released so that normal blood flow can return to the limb of the patient.
Unfortunately, under certain circumstances, the tourniquets are not released from the limb of the patient after a predetermined period of time. Under certain circumstances, medical personnel will neglect to release the tension on the tourniquet after drawing blood. In other circumstances, the person drawing blood becomes distracted and walks away from the patient for an extended period of time. This is a particular problem where the patient is immobilized, unconscious, or unable to release the tension of the tourniquet from around the limb.
The failure to remove the tourniquet is a significant liability problem for hospitals and for medical personnel. Under certain circumstance, when the tourniquet is not removed from the limb of the patient within a predetermined period of time, there can be a significant loss of function in the limb. In other circumstances, death can occur. For example, if a tourniquet is maintained on an unconscious patient, the limb would have to be amputated before the removal of the tourniquet could occur. If the tourniquet is removed after an extended period of time, blood clots can enter the circulation system of the patient. This can often result in death, stroke or severe injury to the patient. As such, it is extremely important for the well-being of a patient that affirmative steps be taken so as to assure that the tourniquet is removed promptly each and every time that it is used.
In the past, various devices have been developed which act on pneumatic-operated tourniquets. These tourniquets are in the nature of blood pressure devices or other apparatuses. After a predetermined period of time, the air is released from the tourniquets so as to allow blood flow to be restored in a prompt manner. Various patents have issued in the past relating to such apparatuses. For example, U.S. Pat. No. 6,746,470, issued on Jun. 8, 2004 to McEwen et al., describes a pneumatic tourniquet adapted for self application by an injured person in a military or emergency situation so as to stop arterial blood loss in an injured arm or leg. This tourniquet includes a bladder having a width dimension and having a length dimension greater than the circumference of an injured limb. A clamping means is used for securing the bladder around the limb at the selected location and adapted for sealing the bladder across the bladder width to establish an inflatable portion of the bladder. This inflatable portion of the bladder is that portion of the bladder that encircles the injured limb at the selected location.
U.S. Pat. No. 6,605,103, issued on Aug. 12, 2003 to Hovanes et al., teaches a system and method for controlling pressure in a surgical tourniquet. A sensor is used to determine when flow past the tourniquet is occurring so that corrective action may be taken. This corrective action can be in the nature of increasing the pressure in the tourniquet or by notifying an operator of the flow past the tourniquet. An acoustic sensor can be used so as to indicate incipient blood flow. When the signals are detected, the tourniquet controller either incrementally increases the pressure in the tourniquet or signals an alarm indicative of the blood flow.
U.S. Pat. No. 6,051,016, issued on Apr. 18, 2000 to Mesaros et al., describes system and method of controlling the pressure in a surgical tourniquet. The pressure within an inflatable cuff surrounding a portion of a limb of a patient is changed by automatically opening a first valve connected to a controller and located in a first conduit between an inflatable bladder and the inflatable cuff when the pressure in the inflatable cuff is different from that in the inflatable bladder. Blood blow is selectively occluded within a portion of a limb of a patient within five seconds. A device is provided for detecting a leak in the tourniquet.
U.S. Pat. No. 5,842,996, issued on Dec. 1, 1998 to Gruenfeld et al., provides an automatic tourniquet system that includes a variable pressure cuff apparatus for applying a variable pressure to a limb or artery of a patient in order to occlude blood flow thereat. A control apparatus is utilized for determining the operative pressure of the variable pressure cuff. An apparatus is provided for estimating the minimum effective cuff pressure required for complete occlusion.
U.S. Pat. No. 5,181,522, issued on Jan. 26, 1994 to J. A. McEwen, shows a tourniquet system that includes an inflatable occlusive band for encircling a limb of a subject and for inflating to apply pressure to the limb in order to occlude blood flow. An inner surface of the band faces the limb. An inflation pressure regulation means responsive to a variable inflation pressure regulation signal regulates the pressure to which the occlusive band is inflated and produces an inflation pressure signal representative of the pressure to which the band is inflated. The tourniquet includes a pressure comparison means that compares the difference between the pressures represented by the inflation pressure signal and the applied pressure signal and generates an alarm signal if the difference exceeds a preassigned limit.
U.S. Pat. No. 3,095,873, issued on Jul. 2, 1963 to A. B. Edmunds Jr., shows a mechanically driven electrical recording Sphygmomanometer. In this device, a screw-type mechanism is provided along the band so as to draw the band closer together for releasing the band.
U.S. Pat. No. 2,614,565, issued on Oct. 21, 1952 to J. K. Packer, shows an automatic tourniquet which includes suitable valves for adding pressure to the limb and for releasing pressure from the limb.
U.S. Pat. No. 4,516,576, issued on May 14, 1985 to G. Kirchner, shows a tourniquet strap or band for restricting blood flow. The tourniquet includes a clamping lock and a strap which is pulled through the clamping lock and wrapped around the arm of a patient. The clamping of the strap in order to form a stanching loop occurs by means of a spring-loaded clamping wedge which clamps the strap against an inner wall of the clamping lock via a clamping plate. By manually displacing the clamping wedge against the force of the spring, the clamping force can be sensitively regulated so that a regulated release of the stanching loop is possible.
U.S. Pat. No. 5,219,356, issued on Jun. 15, 1993 to Harreld et al., provides a disposable tourniquet having an elongated, flat, stretchable band. The band has a pressure-sensitive adhesive face on one side of the band at one end and a release agent on the same face of the band but spaced from the adhesive face. The tourniquet is stored with the adhesive face folded against and adhering to the release agent. It is deployed by peeling the adhesive face away from the release agent, wrapping the tourniquet about the arm and pulling it sufficiently tight, and then adhering the adhesive face to the outside surface of the band to hold the tourniquet in place.
It is an object of the present invention to provide an auto-release tourniquet that automatically releases the tension of the tourniquet after a predetermined period of time.
It is another object of the present invention to provide an auto-release tourniquet that is portable.
It is a further object of the present invention to provide an auto-release tourniquet that is battery-operated.
It is a further object of the present invention to provide an auto-release tourniquet that displays the amount of time in which the tourniquet has been placed on the limb of the patient.
It is further object of the present invention to provide an auto-release tourniquet that sounds an alarm after an predetermined period of time.
It is still another object of the present invention to provide an auto-release tourniquet that allows for the proper tensioning of the tourniquet around the limb of the patient.
It is still further object of the present invention to provide an auto-release tourniquet that is easy to use, relatively inexpensive and easy to manufacture.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.